I'm sorry in advance if this is somewhere in the documentation but I googled it as best I could, but it would be incredibly helpful if somewhere in the documentation it specified the version of Redis that this service is based off of.
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@cranesandcaff Thank you for this detailed feedback. I will get you this information and then make an enhancement request to the content owner to include this detail.
@cranesandcaff If you have a Redis instance deployed, you can find the version information in the properties blade in the Azure Portal:

I realize this does not help those who do not have an instance deployed. Like I said, I will assign to the content owner to best enhance the documentation with deployed version release notes or specific version information.
I ended up using the console and info command. I don't know how I missed that. Is version 4 an option?
@cranesandcaff Please Up Vote and comment on the following entry in the User Voice: Redis Version upgrade from 3.2.X to 4.x.
Thanks for the suggestion! We'll figure out what would be the best place to show the version information. Redis 4.0 should be available in the next few months.
This appears to be resolved with already-existing information available.
We will now proceed to close this thread. If there are further questions regarding this matter, please comment and we will gladly continue the discussion.
@yegu-ms do you have any update on the timeline for availability of Redis v4+? Redis latest stable is now 5.0 and it's hard getting such old versions as 3.x running locally because it's so old it's not even available in many package managers anymore.
@naile - affirming Redis v4 is currently being used by Azure Redis Cache.

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@cranesandcaff If you have a Redis instance deployed, you can find the version information in the properties blade in the Azure Portal:
I realize this does not help those who do not have an instance deployed. Like I said, I will assign to the content owner to best enhance the documentation with deployed version release notes or specific version information.